Throughout the long evolution of aircraft, both light single and twin engine as well as larger commercial and corporate aircraft, there has been no standardization of the multiple flight instrument gauge and indicator display on the aircraft instrument panel. Rather, the placement and arrangement of instruments thereon has always been a matter of available space, convenience, or the aircraft designer's particular preference.
As an elemental matter of continuous experience to every beginning and skilled pilot, transition from one aircraft to another invariably requires restudy and relearning of the location on the panel of the primary and necessary flight instruments before undertaking flight. The position of the instruments has varied from manufacturer to manufacturer as well as in model to model from the same manufacturer over the years.
All panel-mounted indicators and devices are intended to be placed to be viewable by and accessible to the pilot or pilots in handling and utilizing the aircraft. These include fuel gauges, fuel pumps, tachometer, clock, diverse switches for numerous functions as lights, flaps, etc., as well as communication equipment, and vary in location as deemed advisable in arranging the panel area at initial factory assembly or later rework or modification.
There are, however, of the many instruments available, six which are critical to safe handling of the aircraft in flight, especially under weather conditions inimical to visual flight (VFR) as the dark of night, haze, mist, scattered clouds, or undercast, or in any instrument meteorological conditions (IMC) requiring flight by instrument flight rules (IFR) solely by reference to panel instruments without visual assistance from outside the cockpit.
These six instruments comprise the:
(1) Altimeter PA1 (2) Artificial Horizon PA1 (3) Compass PA1 (4) Vertical Speed Indicator PA1 (5) Airspeed Indicator PA1 (6) Turn and Bank Indicator
Ever since the development by Sperry of the gyroscopic artificial horizon more than sixty years ago, substantial development and training effort has been applied to teaching and learning to safely control an aircraft and its flight by reference to these instruments, either as a sole source of flight information, or as an adjunct to limited visual flight ability. Such training has made possible safe takeoffs, flights, and landings for pilots and passengers in less than desirable weather conditions, even in the absence of radio communications.
Even so, as above indicated, the irregular, and non-standardized placement of necessary flight instruments on the panel in any aircraft and between one aircraft and another has handicapped training and learning of the techniques of flying by sole reference to instruments. Instrument flying is demanding, and the random disposition of instruments on the panels of differing aircraft has led to countless recorded instances of loss of control of aircraft under difficult flying conditions by the inability of the pilot to quickly observe, assimilate, and use indicated and accurate information from related but irregularly spaced and positioned directional and rate instruments, frequently resulting in injury and death.
Notwithstanding modern and superb navigational instruments, including radar, global positioning systems, as well as omnirange navigation, ILS and other preplanned terminal area approaches and navigation aids, etc., failure of the pilot to keep the aircraft upright or in a controlled bank, or at a proper altitude, and with an airspeed maintained above stall, by insufficiently rapid scan and perception of instrument panel information available remains a primary cause of accidents.
Efforts have been made in the past to improve the panel format of flight instruments in an attempt to improve the ability of pilots to scan and use the information provided by diverse flight instruments. See, for example, the U.S. Pat. No. 1,836,881, Henderson U.S. Pat. No. 1,924,037, Schulz U.S. Pat. No. 2,398,724, and Gordon U.S. Pat. No. 2,660,977. These patents teach varying grouped arrangements of instruments in a manner seeking to improve the scan of the pilot for quick grasping of the conveyed instrument information, thereby to enhance aircraft control and safety. These prior patents contemplate circular or cruciform arrangements of selected instruments generally representing the vertical and horizontal axes of the aircraft, for example, but do not cooperatively and symmetrically relate the functions and panel positions of each instrument to each other during cross-checking of the same by the pilot.
None of these patents, any more than the present instrument panels extant in aircraft in use today, disclose or suggest the concept of a specifically integrated and symmetrical array of known flight instruments providing unique respective and related aircraft directional and rate information before the pilot's eyes in a proximate, adjacent and symmetrical grouping for reliable and quick assimilation of the related flight indications.